EXECUTIVE CONTROL

Rule Generation and selection: The processes involved in activating task-related goals or rules based on endogenous or exogenous cues, actively representing them in accessible form, and maintaining and using this information to bias attention and response selection during the interval needed to perform the task.

Nominated tasks

• Set-shifting task (Intradimensional/Extradimensional shift task): A paradigm in which the animal first learns to discriminate compound (e.g. multimodal) stimuli on the basis of one dimension (while properties within the other dimension(s) are varied randomly). Upon the acquisition of this set, the rule is shifted such that a previously irrelevant dimension/set is relevant and the first set becomes irrelevant.
• Reversal learning (including probabilistic, 3-choice, and serial reversal paradigms): The reversal of a discrimination rule such that a stimulus previously associated with the correct response (and reward) is now associated with non-reward.

Dynamic adjustments of control: The processes involved in detecting recent conflict or errors in ongoing processing and making rapid (within or inter-trial) adjustments in control and performance.

Nominated task

• Stop-signal task (assessment of post-error slowing): A task requiring the animal to use an external stimulus to cue the interruption of a proponent, already-initiated motor response.

 

WORKING MEMORY

Goal maintenance: The processes involved in maintaining information about task-related stimuli, goals and rules and using this information to bias attention and response selection during the interval needed to perform the task.

Nominated tasks

• Delayed matching/non-matching tasks: This includes operant-box and maze versions by which animal is required to make a choice that matches or does not match a choice made on a previous trial. The time between trials and number of past choices required to remember are varied.

Interference control: the ability to hold required information over time in the face of competing, irrelevant information or intervening events.

Nominated tasks

• N-back task: Individual stimuli are presented serially and animal is cued to report whether a target stimulus occurred 1,2 or more stimuli prior to the cue.

Memory capacity: The size of the 'buffer' or array of items that can be held in memory.

Nominated tasks

• Span tasks: Item or odor span tasks, where animal is required to remember object or location information presented previously. Number of items/locations and total time to retain information is typically varied.

 

ATTENTION

Control of Attention: The ability to guide and/or change the focus of attention in response to internal representations (and prevent interference of this process by external noise).

Nominated tasks ‐ Note: The group considered the 5C-CPT, a variant of the 5CSRT to which a response inhibition component has been added, and that each of these three tasks studies attentional control as a function of signal probability and salience. The tasks are complementary in their ability to isolate the effects of 1) size of the attentional field, 2) interference, 3) response bias or behavioral inhibition, and 4) detection modes (recent history of signal versus non-signal decisions).

• Distractor Sustained Attention Task: Requiring animal to report (with different responses) whether or not a signal occurred. The salience and probability of the signal, and level of external noise (non-relevant stimuli), are varied.
• 5-choice serial reaction time task: Requiring animal to detect and report stimuli occurring at one of multiple possible locations.
• 5-choice continuous performance task: Similar to 5-choice serial reaction time task except with addition of non-signal trials that are reported by response inhibition.

 

MOTIVATION AND REINFORCEMENT LEARNING

The group recommended that Motivation and Reinforcement Learning should be considered as separate constructs, each with its own set of procedures used to assess it.

Reinforcement Learning: Acquisition of an instrumental response in order to gain access to an appetitive (positive reinforcement) outcome or avoid an aversive outcome (negative reinforcement). Positive reinforcement was considered the process of greatest relevance to avolition in schizophrenia.

Nominated task

• Probabilistic Reinforcement Learning: Assessing acquisition and adjustment an instrumental response according to probability of the reinforcer.

Motivation: The valuation of an outcome (the conditioned stimulus or reinforcer) and expending work or guiding behavior on the basis of the value or probability of that outcome.

Nominated tasks

• Effort-related tasks (e.g. Progressive Ratio): Progressively or randomly increasing the effort requirement (response ratio, height of barrier, duration of responding) for earning reward.
• Outcome Devaluation and Contingency Degradation task: Assessing impact of reward devaluation (through saturation or negative association) on positively-reinforced responding.
• Pizzagalli Task: Assessment, using a difficult discrimination task, of the impact of differential reinforcement probability on response bias towards the stimulus/response that is more frequently reinforced.
• Pavlovian Autoshaping: Assesses Pavlovian appetitive conditioning to a cue in the context of an instrumental response that does not depend on the cue.

 

PERCEPTION

Gain control: The processes whereby neurons adapt responses and animals adjust behavior to take into account an immediate perceptual context, done in order to make best use of a limited dynamic signaling range.

Nominated tasks

• Prepulse inhibition of the startle reflex (already mature): Attenuation of a startle response as a function of immediate pre-exposure to a sub-threshold stimulus in same modality
• Mismatch negativity and related responses to changes stimulus characteristics ('odd ball' or frequency-variation paradigm): Neural and behavioral responses to a change in stimulus characteristics

Integration: The processes linking the output of neurons that typically encode local attributes of a scene into a global complex structure, more suitable to the guidance of behavior.

Nominated tasks (applied primarily in non-human primates)

• Coherent motion detection: Animals (or neurons) respond when coherent motion of multiple parts (usually points or line segments) is detected (outcome measure = threshold).
• Contour detection: Animals (or neurons) respond when elements form a contour (outcome measure = threshold).

 

OBJECT, RELATIONAL AND LONG-TERM MEMORY

Relational encoding and retrieval: The processes involved in memory for stimuli/elements and how they were associated with coincident outcomes (stimuli, context or events).

Nominated tasks

• Paired Associate Learning: Requiring the use of one stimulus to cue the choice of a subsequent stimulus when the latter is presented among two more stimuli.
• Object in Place Scene Learning: A variant of conditional discrimination requiring the animal to use a complex visual background (or context) to guide a choice between one of two possible cued responses (cues are presented in foreground).

 

SOCIAL/EMOTIONAL PROCESSING

The animal paradigms group focused on social signal processing.

Social recognition: The ability to detect, recognize social cues emitted from a con-specific and respond appropriately.

Nominated tasks

• Social recognition/preference: Variants include comparing responses to novel versus familiar social objects, social objects versus neutral or non-living objects. Outcome measures include approach or exploration, species-appropriate social behavior, vocalization, autonomic status.
• Emotional and intention recognition: Animals are shown video/audio presentation of social signals from conspecifics (e.g. facial expressions, body movements, vocalizations). Outcome variables include gaze aversion; gaze choice; autonomic output; gaze following/scan pattern/speed; reaction time to emotional and non-emotional stimuli. This can be modified to require an operant response when animal identifies a cue within a certain class (e.g. aggression).